4A vs 4H

[bouvier]

Under what conditions/terrain would I select 4H if I have 4A available?

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[Oxford_Powerboost]

Not many, 4A gets through a lot. But my rule of thumb is 4A on public streets if it’s snowy or very greasy/wet. If you find some unplowed backroads, maybe 4Hi (deep snow/sand mode goes into 4Hi and I found i found that mode much better when getting through 8+ inches of unplowed snow, though I think it was more the drive mode than 4Hi vs 4A). Then usually 4Hi where you are off road/on beach and want to make sure you don’t lose momentum by keeping a 50/50 torque split vs 4A varying power back and forth.

Also, you might see a lot of 4A misinformation out there. It is not 2WD until 4WD is needed. It is a sort of AWD system with continuously variable torque split front to rear that the computer controls based on throttle, steering, wheel spin, drive mode, and other factors

 

[pkinneb]

Not many, 4A gets through a lot. But my rule of thumb is 4A on public streets if it’s snowy or very greasy/wet. If you find some unplowed backroads, maybe 4Hi (deep snow/sand mode goes into 4Hi and I found i found that mode much better when getting through 8+ inches of unplowed snow, though I think it was more the drive mode than 4Hi vs 4A). Then usually 4Hi where you are off road/on beach and want to make sure you don’t lose momentum by keeping a 50/50 torque split vs 4A varying power back and forth.

Also, you might see a lot of 4A misinformation out there. It is not 2WD until 4WD is needed. It is a sort of AWD system with continuously variable torque split front to rear that the computer controls based on throttle, steering, wheel spin, drive mode, and other factors

This ^^^

 

[Bryan Simon]

4A could be selected and then erased from memory
4Hi is something you will notice right away as you pull out of your driveway and the truck gets all bound up, can also cause damage if you are persistent about using it on hard dry roads.

the 4A transfer case has a differential inside that allows the front and rear to move at different speeds when necessary.

I have a 4x4 Trailblazer that is always in 4A as she has no idea what the rest of the buttons are for, and I’d prefer if she did not experiment.

my 4x4 pickups do not have that feature and the old Chevy has lockers front and rear so 4x4 on anything dry and hard is a definite no no. And even in 2wd, on wet roads is interesting in a turn and it’s pretty easy to point the front of the truck south and have the rear keep going east.

performance wise, 4A will balance traction to where it is needed to keep all four holding onto the ground. May not be something you would use while climbing or mudding but generally fine for set and forget.
You most likely would take a mpg hit on that setting tho.

 

[gtotco]

4A could be selected and then erased from memory
4Hi is something you will notice right away as you pull out of your driveway and the truck gets all bound up, can also cause damage if you are persistent about using it on hard dry roads.

the 4A transfer case has a differential inside that allows the front and rear to move at different speeds when necessary.

I have a 4x4 Trailblazer that is always in 4A as she has no idea what the rest of the buttons are for, and I’d prefer if she did not experiment.

my 4x4 pickups do not have that feature and the old Chevy has lockers front and rear so 4x4 on anything dry and hard is a definite no no. And even in 2wd, on wet roads is interesting in a turn and it’s pretty easy to point the front of the truck south and have the rear keep going east.

performance wise, 4A will balance traction to where it is needed to keep all four holding onto the ground. May not be something you would use while climbing or mudding but generally fine for set and forget.
You most likely would take a mpg hit on that setting tho.

FWIW I think there is a mileage hit but in the realm of normal. I sometimes just leave it on 4A in winter because even when roads are clear you hit those occasional spots. I end up losing MAYBE 1 mpg but it’s in the margin of error and I do worse in winter even in 2H so it’s a bit hard to tell. I notice a bit of drag driving in 4A so there should be some penalty but it seems pretty small.

 

[RoccoL]

Under what conditions/terrain would I select 4H if I have 4A available?

Not many, 4A gets through a lot. But my rule of thumb is 4A on public streets if it’s snowy or very greasy/wet. If you find some unplowed backroads, maybe 4Hi (deep snow/sand mode goes into 4Hi and I found i found that mode much better when getting through 8+ inches of unplowed snow, though I think it was more the drive mode than 4Hi vs 4A). Then usually 4Hi where you are off road/on beach and want to make sure you don’t lose momentum by keeping a 50/50 torque split vs 4A varying power back and forth.

Also, you might see a lot of 4A misinformation out there. It is not 2WD until 4WD is needed. It is a sort of AWD system with continuously variable torque split front to rear that the computer controls based on throttle, steering, wheel spin, drive mode, and other factors

Thank you for the thorough explanation! I too was curious.

 

[RJL1400]

Not many, 4A gets through a lot. But my rule of thumb is 4A on public streets if it’s snowy or very greasy/wet. If you find some unplowed backroads, maybe 4Hi (deep snow/sand mode goes into 4Hi and I found i found that mode much better when getting through 8+ inches of unplowed snow, though I think it was more the drive mode than 4Hi vs 4A). Then usually 4Hi where you are off road/on beach and want to make sure you don’t lose momentum by keeping a 50/50 torque split vs 4A varying power back and forth.

Also, you might see a lot of 4A misinformation out there. It is not 2WD until 4WD is needed. It is a sort of AWD system with continuously variable torque split front to rear that the computer controls based on throttle, steering, wheel spin, drive mode, and other factors

XLT doesn't seem to come with 4A

 

[n8dgr8]

Not sure why, but 4A does not seem to work well with icy driveways and parking spots. It seems to lurch at very low speeds.

 

[Buyer2021]

Is my understanding correct?

• "4x4 ESOF" does not have the "4A" setting (only 2H, 4H, and 4L)
• 4x4 ESOF is standard on all 2022 4x4 XL, XLT, and Tremor
• "Two-Speed Automatic 4WD" does have the "4A" setting (in addition to 2H, 4H, and 4L)
• Two-Speed Automatic 4WD is standard on all 2022 4x4 Lariat, KR, Platinum, Limited, and Raptor* (except when snow-plow prep package is ordered, which includes 4x4 ESOF instead)
• Both systems have Neutral Towing Capability (can be towed with all wheels on the ground)
• *Raptor is with mechanical locking 4WD, others with Two-Speed Automatic 4WD are electronic

Thanks In Advance for confirming or correcting.

 

[DBL R]

Not sure why, but 4A does not seem to work well with icy driveways and parking spots. It seems to lurch at very low speeds.

probably a few reasons, one reason is that the front and rear drivetrain isn’t locked together so the system is measuring slip at the wheel and changing clutch pressure to send additional power to tires with more grip. With my parking lot hooning it also seems that 4a will engage abs braking to apply torque vectoring when Corning or applying throttle with the wheels turned. 4X4 seems to handle uniform conditions better than 4a where 4a is better with partially covered roads or roads with varying levels of slickness.

 

[Oxford_Powerboost]

XLT doesn't seem to come with 4A

Correct. It is a feature on Lariat and up trucks. (Or 402A tremor). For those without it, the axles are mechanically locked instead of electronically. You’ll need to be more deliberate with the non 4A transfer cases, as 4Hi can’t slip to allow the truck to turn in hard surfaces

 

[Chili]

Is 4a really not notable at all on dry pavement? My XLT doesn't have it but past Chevys with it were slightly noticeable. Ot bad, but it felt just a tad off on dry.

 

[Tomatoboy]

Is 4a really not notable at all on dry pavement? My XLT doesn't have it but past Chevys with it were slightly noticeable. Ot bad, but it felt just a tad off on dry.

On my Lariat I can absolutely tell if 4A is on versus 2H on dry pavement, because the front wheels are getting power, so on say hard acceleration from a stop, you do feel the difference. There is a change in handling, it feels exactly like you’d expect from any other clutch based AWD system in any longitudinal mount SUV when in 4A, so it’s noticeable when switching back to 2H in my experience. It’s not dramatic on dry pavement, but I can feel it.

Since Ford has said it is safe to use in all conditions, I leave my truck in 4A as a default, in case my wife drives it (she’s not as familiar with RWD). That said, I do usually turn off 4A on sunny days with dry pavement once I get on the highway, since I get a modest (maybe 0.5mpg) fuel economy boost in 2H.

As for the earlier discussion about when to use 4H vs 4A, having 4A and seeing how the system anticipates need, when I do take my truck somewhere I need the 4WD system, I usually start off in 4A and only enable 4H when I see something coming the system cannot anticipate such as a massive mud wallow.

 

[Chili]

The 4a systems are just awesome. I had planned on adding it to my 2020 but since that's a lemon I want to wait a while to make sure the 22 is sticking around. As it understand it, it's possible to add to the 14th gens as well with just a new tcase, few parts and forscan.

 

[powerboatr]

my truck is 4A almost 100% of the time
MPG hit? maybe a tad
but my 2016 exp ran 4A almost 100% of time as well 19.1 lifetime mpg
for us here, 4A is great because our roads are not hmmmm unslick
a little rain and its slippery . plus we have lots of grit or loose stuff from the oil rig trucks dropping it off onto the roads
normal on street , rain, snow etc i use 4A. if its a heavy pack like the snow freak snow of a few years back i ran 4H all week . in the 16 exp

the 22 4A is more sensitive IMO to tire slip or loss of traction and applies power where its needed very smooth compared to the 16.
my river rock driveway (about 60 feet) tested it a few weeks back when i pulled the trailer up and across it loaded with 3600lbs of rocks, the truck climbed, slowed when trailer wheels came off the road to the transition hump to the rocks. i felt a wheel slip, it then grabbed and i kept moving. i did engage the locker right after to just give me more control.

4A is a great option, select it and leave it.

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